Hike Grinnell Mountain, Ten Thousand Foot Ridge, Lake Peak San Bernardino National Forest, CA

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Jul 10, 2026 — A few years ago I hiked to San Gorgonio Mountain via the South Fork and Dry Lake loop, a classic route that offers a quieter alternative to the busy Vivian Creek Trail while still reaching Southern California’s highest summit. My SoCal peaks to-do list has shrunk to nearly zero, so I dragged Chris up to these far lesser-visited neighbors on the mountain’s north side: Grinnell Mountain, Ten Thousand Foot Ridge, and Lake Peak.

These summits were once most easily reached from the Fish Creek Trail, but that route was heavily damaged by flooding and remains closed with no announced reopening as of July 2026. That meant taking the scenic route, adding plenty of extra trail miles before the off-trail fun even began.

The South Fork Trail made for an enjoyable and casual approach, leading gradually through an old burn area before entering a portion of spared forest. The grade stayed refreshingly civilized as the trail crossed South Fork Meadows and continued toward Dry Lake, with occasional openings revealing the massive upper slopes of San Gorgonio overhead. Dry Lake itself was a filled with water, quite different from my last visit here.

From Dry Lake we followed the Lodgepole Trail up to Fish Creek Saddle. It proved noticeably rougher than the impeccably maintained South Fork Trail, becoming steeper and occasionally faint. From Fish Creek Saddle we headed north to Grinnell Mountain on a social trail that conveniently wove around much of the deadfall. The summit itself was just a checkbox due to limited views, so we returned to the saddle and began an ascending traverse toward Ten Thousand Foot Ridge.

This ridgeline walk ended up being the highlight of the day. It rolled over a series of gentle undulations with expansive views in nearly every direction and a unique angle toward San Gorgonio. Faint paths appeared here and there, and a steeper final climb led to the summit of Ten Thousand Foot Ridge.

On the return, we detoured to Lake Peak. The connecting ridge was a bit rougher, littered with deadfall and scattered boulders that kept things interesting without becoming difficult. Until recently, Lake Peak’s highest point was believed to be the eastern summit, but modern LiDAR data identifies the western bump, now labeled Lake Peak Southwest, as the true high point, so naturally we made sure to stand on the correct pile of rocks.

Rather than retrace our steps yet again, we decided to make a partial loop by descending west from Lake Peak – Southwest. The descent had only light brush, and soon we reached the Dry Lake Trail, which led back down to Dry Lake, completing our little extracurricular loop add-on.

PEAKS ON HIKE
Elevation (ft) / Prominence (ft)

Peaks on hike

Elevation

Prominence

Grinnell Mountain

10287 ft

491 rise

Ten Thousand Foot Ridge

10091 ft

311 rise

Lake Peak

10161 ft

10 rise

Lake Peak - Southwest

10177 ft

344 rise

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South Fork Trailhead.

A cabin within Horse Meadows.

Entering the San Gorgonio Wilderness.

South Fork Trail leads through a burn area slowly recovering.

Junction, we kept left to head up the Dry Lake Trail.

Ascending along the Dry Lake Trail.

Nearing Dry Lake.

Dry Lake, currently full.

Dry Lake, San Gorgonio Mountain in the distance.

The Lodgepole Trail was steep and faint at times, leading to Fish Creek Saddle.

From Fish Creek Saddle, heading up to Grinnell Mountain. A social trail was visible at times.

View back as we near Grinnell Mountain.

Grinnell Mountain view north. Meh.

From Fish Creek Saddle, we made an ascending traverse to gain the ridgeline leading to Ten Thousand Foot Ridge.

Along the way to Ten Thousand Foot Ridge.

Ten Thousand Foot Ridge ahead.

Steep push to Ten Thousand Foot Ridge summit.

Ten Thousand Foot Ridge summit, view west. San Gorgonio Mountain left, Grinnell Mountain right.

Close-up toward the ridge we just cam across (right), and San Gorgonio Mountain (left).

Ten Thousand Foot Ridge summit, view south toward Mount San Jacinto.

View toward Joshua Tree National Park.

We backtracked and headed up to Lake Peak. Lots of deadfall.

Lake Peak (old high point).

Coming down the west ridge from Lake Peak - Southwest (new high point).

We joined the Dry Lake Trail.

View back along the Dry Lake Trail.

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Hire/refer me as a web developer or send me a few bucks if you find my site useful. I’m not sponsored, so all fees are out-of-pocket and my time preparing trip reports is unpaid. I really appreciate it!